In recent years, various services are being provided by utilizing a network. In addition, due to popularization of mobile communications and the like, users of network services are becoming to perform accessing from network environments of various communication speeds. In such a situation, since service providers cannot distinguish users by communication speeds, in many cases, service providers provide services by using a band that allows many users to use without problems. However, in this case, a problem arises that a user who uses a broadband network environment cannot receive services with quality that should be originally usable. Also, for users who utilize a narrowband network environment, there arises a problem that quality deterioration will occur when using the environment.
Therefore, with respect to voice/video communication services, which are services that are particularly susceptible to the network quality, efforts are being made to dynamically change provision quality of the service according to quality indicators that can be measured by users, such as occurrence of stop of reproduction, or occurrence of break of voice or the like while the services are being provided. This is a control scheme seen in MPEG-DASH and the like in recent years (refer to reference 1, for example).
In addition, like a CDN (Contents Delivery Network), a technique is also widespread for selecting, in advance, a server closest to a user's IP address and the like so as to select a server that the user can use comfortably as much as possible (refer to reference 2 for example).